1. Field of the Invention
The present invention relates to a fuel tank to be mounted on a straddled type vehicle, especially on a motorcycle.
2. Description of the Prior Art
Heretofore, in a motorcycle, a fuel tank was formed to have an inverse U-shaped transverse cross-section with its lower section bifurcated, because the fuel tank was mounted on a vehicle body in such manner that the fuel tank may straddle a main pipe connected to an upper portion of a head pipe from the above.
In such a fuel tank, although the fuel filled in both the left and right branch portions of the tank communicates with each other in the state of a high fuel level, if the fuel level becomes low, the fuel is separated as accommodated in the left and right branch portions, respectively, due to the central communicating portion being held at a high level so as to avoid the main pipe. Consequently, in the case where a fuel cock is provided in either one of the left and right branch portions, the fuel would mostly remain in the branch portion not provided with the fuel cock, and hence the practical capacity of the fuel tank would be reduced. Even if the fuel should flow into the branch portion on the opposite side, that is, into the branch portion provided with the fuel cock due to tilting of the vehicle body or the like, the amount of the transfered fuel would be limited.
If the depths of the left and right branch portions are made shallow in order to avoid this shortcoming, then the level of the main frame is lowered, and hence the arrangement of the engine and the rear cushion would be restrained. Or, if the lower parts of the left and right branch portions are cut away, then the tank capacity would be reduced, and moreover, design of the appearance is limited. Furtheremore, if fuel cocks are provided in both the left and right branch portions, then when one is going to interrupt a fuel passageway, the driver may possibly forget to close either one of the left and right cocks. In addition, upon mounting and dismounting the fuel tank, the work of connecting and disconnecting the fuel pipes would become troublesome.